“Dunkirk” is a war movie, a thriller, an “art” film, and a true tale of survival, heroism, and selflessness. During the telling of its three related stories that eventually converge into one, viewers will be so caught up in what’s going on, they’ll either be sitting forward, urgently grabbing their armrests, or they’ll be pressed back into the seats, unable to move.

Most Americans have probably heard of Dunkirk, the French seaport across the English Channel from Dover. But because the historical events told here took place in 1940, well before the U.S. got involved in WWII, not many Americans know what happened there, what’s become known as the Dunkirk Evacuation.

The opening moments of the film occur long after British and French military forces have become trapped on the shore by German forces. Somewhere between 300,000 and 400,000 Allied soldiers were stuck on that beach hoping, as the text says, “for their deliverance,” to be rescued. The cameras pan across the sand, with those soldiers in orderly lines, facing the ocean, able to see a couple of big British destroyers way out there. But the water is too shallow for the ships to get close enough to rescue them, and they’re too far away for the men to make it by swimming. While this is happening, German planes are strafing and bombing the beach, raining down pandemonium and death.

This is a film by Christopher Nolan, the writer-director who has given us the fierce and brooding “Dark Knight” trilogy, as well as the fantastic but often hard-to-follow “Memento,” “Inception,” and “Interstellar.” “Dunkirk” has a different, far more accessible kind of complexity. It’s an ensemble piece, so no one or two actors or characters stick out from the others. But it also features three separate, but connected stories. One happens on the beach and on the long, pier-like structure called the mole, and covers events that lasted almost a week. The second is a day-long look at the British civilians across the Channel who, after having been asked to help by the British military, make a concerted effort to take part in the rescue of the soldiers. The third happens over the course of an hour, with cameras inside the British Spitfire fighter planes that were on their way to the beach to go up against the German Messerschmidts that were wreaking havoc on the trapped men.

It’s Nolan’s amazing script structure of three stories: On the land, at sea, and in the air, happening at once, and intertwining, and sometimes bouncing around in time, that makes the film so exciting and intense. Of course, on top of that, what pushes everything into areas of greatness is that the script also gives us perceptive characters stories within those stories: Kenneth Branagh’s Commander Bolton on the beach, trying to figure out, in this hopeless situation, how to save his men; Mark Rylance’s Mr. Dawson, who is speeding toward Dunkirk in his pleasure boat, after hearing that “some men across the Channel need taking off”; and Tom Hardy’s Farrier, a Spitfire pilot who is fast running out of fuel, but is determined to shoot the enemy out of the skies.

An additional, equally important, and extremely effective component, is the score by Hans Zimmer. A constant presence, it’s loud, pulsing, and often dissonant, and is a perfect complement to the frustration and desperation being portrayed, more often than not with very little dialogue.

“Dunkirk” is surprisingly short, tight, and lean for a Nolan film, clocking in at only 106 minutes (“The Dark Knight Rises” ran 164 minutes, “Interstellar” was 169), but this is simpler, more straightforward storytelling: Rescue these guys. Still, we get spectacular visual effects, especially in the dogfights between the Spitfires and Messerschmitts, and crystalline cinematography that sets the IMAX cameras right in the midst of the chaos on the beach and up close in the faces of the people in the small boats and planes (it must be noted that Tom Hardy once again has his face mostly covered, as he did in “Mad Max” and “The Dark Knight Rises”).

To experience the full magnificence of “Dunkirk” do your best to see it in a 70-millimeter presentation on film, not digitally. It is outstanding, breathtaking moviemaking.